Paper-blocking mechanism and printer using the same

ABSTRACT

A paper-blocking mechanism is disposed in a printer. The printer includes at least a main body and an exit roller. The paper-blocking mechanism includes a stopper portion and a stopper elastic element. The stopper elastic element is fixed on the printer and is compressibly connected with the stopper portion. When the tail of the paper leaves the stopper portion, the stopper elastic element drives the stopper portion to rise to be higher than the surface of the exit roller to block the paper exit lest the paper might be back-rolled and jammed.

This application claims the benefit of Taiwan application Serial No. 96139743, filed Oct. 23, 2007, the subject matter of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates in general to a paper-blocking mechanism and a printer using the same, and more particularly to a paper-blocking mechanism preventing the paper from being back-rolled and a printer using the same.

2. Description of the Related Art

FIG. 1 a structural diagram of a conventional printer with an auto sheet feed (ASF). As indicated in FIG. 1, the paper 2 placed on the paper frame 4 is fed into the printer for printing via the pick-up roller 20. After the printing is completed, the paper is conveyed via the feed roller 30 and the exit roller 40 to leave the printer. The feed roller 30 and the exit roller 40 are linked by a synchronous belt (not illustrated) and rotate synchronously.

FIGS. 2A-2B show conventional relationships between a feed roller and a pick-up roller in a paper-feeding state and a paper-printing state respectively. The pick-up roller 20 and the feed roller 30 are driven by the same motor 50, but the pick-up roller 20 is linked to or separated from the motor 50 via the control of an ASF clutch 60. In the paper-feeding state, as indicated in FIG. 2A, the ASF clutch 60 is engaged with the gear set of the pick-up roller 20 such that the rotation of the motor 50 is transmitted to the pick-up roller 20 for taking paper. Meanwhile, the motor 50 rotates anti-clockwise, so that the pick-up roller 20 rotates clockwise to take paper. Meanwhile, the feed roller 30 and the pick-up roller 20 rotate in the same direction, but the rotating direction of the feed roller 30 is opposite to the paper-outputting direction. As the feed roller 30 and the exit roller 40 of FIG. 1 are linked by a synchronous belt and rotate synchronously in the same direction, the rotating direction of the exit roller 40 is also opposite to the paper-outputting direction.

In the printing state, as indicated in FIG. 2B, the ASF clutch 60 and the gear set of the pick-up roller 20 are separated, so that the motor 50 only drives the feed roller 30. Meanwhile, the motor 50 rotates clockwise so that the feed roller 30 and the exit roller 40 rotate in an anti-clock direction which is the same with the paper-outputting direction. When the pick-up roller 20 takes paper after the printing is completed, if the tail of a paper still does not completely leave the exit roller 40, the paper will be back-rolled and jammed because the exit roller 40 rotates in a direction opposite to the paper-outputting direction.

Besides, during the process of conveying a paper, the static electricity generated by the friction between the paper and the roller will cause the paper to be sucked on the exit roller and result in paper-jamming.

SUMMARY OF THE INVENTION

The invention is directed to a paper-blocking mechanism and a printer using the same are provided. The paper-blocking mechanism blocks an outputted paper lest the paper might be back-rolled by the exit roller and jammed.

According to a first aspect of the present invention, a paper-blocking mechanism disposed in a printer is provided. The printer includes at least an exit roller. The paper-blocking mechanism juxtaposed with the exit roller includes a stopper portion and a stopper elastic element. When a paper passes by the exit roller, the stopper portion is lower than the surface of the exit roller due to the pressure by paper. The stopper elastic element is fixed on the printer and compressibly connected with the stopper portion. When the tail of the paper leaves the stopper portion, the stopper elastic element drives the stopper portion to rise to be higher than the surface of the exit roller.

According to a second aspect of the present invention, a printer including a main body, an exit roller and a paper-blocking mechanism is provided. The exit roller and the paper-blocking mechanism are juxtaposed on the main body. The paper-blocking mechanism includes a stopper portion and a stopper elastic element. When a paper passes by the exit roller, the stopper portion is lower than the surface of the exit roller due to the pressure by the paper. The stopper elastic element is fixed on the main body and compressibly connected with the stopper portion. When the tail of the paper leaves the stopper portion, the stopper elastic element drives the stopper portion to rise to be higher than the surface of the exit roller.

The invention will become apparent from the following detailed description of the preferred but non-limiting embodiments. The following description is made with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 (Prior Art) shows a structural diagram of a conventional printer with an ASF;

FIGS. 2A-2B (Prior Art) show conventional relationships between a feed roller and a pick-up roller in a paper-feeding state and a paper-printing state respectively;

FIG. 3 shows a schematic view of a printer according to a first embodiment of the invention;

FIG. 4 shows a lateral view of a partial structure of the printer in FIG. 3 according to the first embodiment of the invention;

FIG. 5A shows an enlarged view of a paper-blocking mechanism in FIG. 4 before the paper is outputted;

FIG. 5B shows an enlarged view of the paper-blocking mechanism in FIG. 4 after the paper is outputted; and

FIG. 6 shows a lateral view of a partial structure of a printer according to a second embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION First Embodiment

Referring to both FIG. 3 and FIG. 4, a schematic view and a lateral view of a printer according to a first embodiment of the invention are respectively shown. The printer includes a main body 100, a feed roller 160, an exit roller 120 and a paper-blocking mechanism 110. The exit roller 120 is disposed on the main body 100. When printing a paper 10, the paper is driven by the feed roller 160 to enter a printing area. After the printing is completed, the paper 10 is taken by the paper-retaining mechanism 130 and the exit roller 120 disposed on the main body 100 to leave the paper exit 5. After the paper 10 is outputted completely, the paper 10 will fall onto a tray 150.

The paper-blocking mechanism 110 is disposed on the main body 100 via the connection to a spindle 116. The paper-blocking mechanism 110 is rotatable with the spindle 116. The paper-blocking mechanism 110 includes a stopper portion 114 and a stopper elastic element 112. During the outputting process of the paper 10, the stopper portion 114 is lower than the surface of the exit roller 120 due to the pressure by the paper 10. The stopper elastic element 112 is connected to the spindle 116 and compressibly connected with the stopper portion 114 for providing the stopper portion 114 with an elastic force to support the paper 10. After the paper 10 is released from the exit roller 120, the stopper elastic element 112 drives the stopper portion 114 to rise to be higher than the surface of the exit roller 120 to avoid the paper 10 being back-rolled. In the present embodiment of the invention, the stopper elastic element 112 is exemplified as a spring, and the paper-retaining mechanism 130 includes a star wheel 132 and a retaining elastomer 134. The retaining elastomer 134 is a spring disposed on the main body 100 for providing the star wheel 132 with an elastic force to retain the paper 10.

As indicated in FIG. 4, the stopper portion 114 includes a suspension arm 114 a and an extension part 114 b, wherein one end of the suspension arm 114 a is linked to the spindle 116, and the extension part 114 b is disposed in the other end of the suspension arm 114 a and extended in the outputting direction of the paper 10.

Referring to FIGS. 5A and 5B, an enlarged view of a paper-blocking mechanism in FIG. 4 before and after the paper is outputted are respectively shown. As indicated FIG. 5A, the paper-retaining mechanism 130 and the exit roller 120 in FIG. 4 retain the paper 10 so that the paper 10 is strained to press the stopper portion 114 downwards. Thus, before the paper 10 leaves the paper exit 5, the stopper portion 114 is pressed downwards by the strain force for allowing the paper 10 to pass smoothly. Meanwhile, the stopper elastic element 112 linked to the stopper portion 114 is compressibly connected with one end of the suspension arm and stores up an elastic force. As indicated in FIG. 5B, when the tail of the paper 10 leaves the stopper portion 114, the elastic force stored up by the stopper elastic element 112 drives the stopper portion 114 to rise so that the extension part 114 b is higher than the surface of the exit roller 120. Despite the paper 10 is sucked on the exit roller 120 due to static electricity or the exit roller 120 is reversed, the paper 10 will not be driven to the paper exit 5 and jammed.

Furthermore, the material of the stopper portion 114 may include a conductive material made of metal or plastics doped with metallic powders. Thus, the electrostatic charges stored up on the paper 10 will be drained lest the paper 10 might be sucked on the exit roller 120.

Anyone who is skilled in the technology of the invention will understand that the technology of the invention is not limited thereto. As indicated in FIG. 3, the printer of the invention may further include a second paper-blocking mechanism 170 disposed on the main body 100 at an interval with the paper-blocking mechanism 110. Thus, the paper of different sizes can correspond to the paper-blocking mechanism deposed in different positions to avoid paper jamming. Also, the number of the paper-blocking mechanism is not limited to 1 or 2 but is determined according to the size and type of the corresponding paper.

Second Embodiment

Referring to FIG. 6, a lateral view of a partial structure of a printer according to a second embodiment of the invention is shown. The present embodiment of the invention differs with the first embodiment in that the second embodiment further includes a detecting device 180 opposite to the stopper portion 114 and disposed on the main body 100. As for other elements similar to the first embodiment, the same designations are used and are not repeated here. The detecting device 180 is a contact type sensor. Whether the paper 10 is released from the exit roller 120 is determined according to the contacting state between the detecting device 180 and the stopper portion 114. For example, when there is no paper, the detecting device 180 and the stopper portion 114 contact each other. When the paper is inputted, the stopper portion 114 is pressed downwards. Meanwhile, the detecting device 180 no more contacts the stopper portion 114, and the detecting device 180 outputs a signal to inform the printer that the paper is already inputted. After the paper is outputted completely, the detecting device 180 contacts the stopper portion 114 again. Meanwhile, the detecting device 180 again outputs another signal to inform the printer that the paper has left completely. Such design assures that the exit roller 120 will not be reversed unless the stopper portion 114 bounces back, hence avoiding paper-jamming.

According to the paper-blocking mechanism and the printer using the same disclosed in the above embodiments of the invention, a paper-blocking mechanism formed by a stopper elastic element and a stopper portion effectively avoids the paper being sucked on the exit roller and jammed. Preferably, the stopper portion can be made from a conductive material to drain the electrostatic charges. Besides, a detecting device can be disposed to assure that the exit roller cannot be reversed unless the paper is completely outputted and released from the exit roller and that the paper-blocking mechanism functions effectively.

While the invention has been described by way of example and in terms of a preferred embodiment, it is to be understood that the invention is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures. 

1. A paper-blocking mechanism disposed in a printer comprising a main body and an exit roller, wherein the paper-blocking mechanism comprises: a stopper portion disposed on the main body and juxtaposed with the exit roller; and a stopper elastic element fixed on the main body and compressibly connected with the stopper portion, wherein when a paper passes by the exit roller, the stopper portion is lower than a surface of the exit roller due to a pressure by the paper, and when the tail of the paper leaves the stopper portion, the stopper portion is driven by the stopper elastic element to rise to be higher than the surface of the exit roller.
 2. The paper-blocking mechanism according to claim 1, wherein the stopper portion comprises a suspension arm and an extension part, the stopper elastic element is compressibly connected with one end of the suspension arm, and the extension part is disposed in the other end of the suspension arm and extended in an outputting direction of the paper.
 3. The paper-blocking mechanism according to claim 1, wherein the stopper elastic element is a spring.
 4. The paper-blocking mechanism according to claim 1, wherein the material of the stopper portion comprises a conductive material.
 5. The paper-blocking mechanism according to claim 4, wherein the conductive material is made of metal or plastics doped with metallic powders.
 6. The paper-blocking mechanism according to claim 1, further comprising a detecting device opposite to the stopper portion and disposed on the main body for detecting a paper-outputting state of a paper according to a contacting state between the detecting device and the stopper portion.
 7. A printer, comprising: a main body having a paper exit; an exit roller disposed on the main body; and at least one paper-blocking mechanism according to claim
 1. 8. The printer according to claim 7 further comprising a spindle disposed in the main body, wherein the paper-blocking mechanism is linked to the spindle and rotatable with the spindle.
 9. The printer according to claim 7 further comprising a detecting device, further comprising a detecting device opposite to the stopper portion and disposed on the main body for detecting a paper-outputting state of a paper according to a contacting state between the detecting device and the stopper portion. 